The electromagnetic spectrum is becoming increasingly crowded due the proliferation of wireless systems. Commercial and military applications face performance degradation due to the proximity of multiple high power systems. The presence of high power interference can even make detection of desired signals impossible. A multiplicity of filters is one method to mitigate performance degradation. The usual way to create such a filter bank for wideband telecoms applications is to use analog ultrasonic Surface Acoustic Wave (SAW) or bulk wave filters, micromechanical filters, or dielectric resonators. Other approaches digitize the whole band of interest and then synthesize whatever assortment of filters is necessary.
Wideband applications, dynamic range considerations and cost limit the utility of whole-band digital approaches. Fixed banks of analog filters with their attendant lack of agility are not effective at reducing interference in the highly dynamic emerging situations.